This invention relates to roof mounted structures and more particularly to a roof curb adapter for joining roof-top equipment to a base curb.
On buildings having a built-up roof, i.e. a roof of asphalt, tar paper, etc., roof integrity problems occur when roof-top equipment such as heating, ventilating and air-conditioning equipment have been installed subsequent to the construction of the roof. When, for example, the equipment size cannot be determined before the roof is constructed, finished roofs in the prior art originally had to be cut at a later time for receiving the equipment. Obviously cutting through the roof reduces substantially the structural integrity of the roof and, in spite of flashing, results in leakage problems.
To improve this situation, the prior art has provided in metal roof frame structures such as in industrial buildings and shopping centers, a metallic box-like structure having a flat platform, known as a roof curb, which is installed on the roof during initial roof construction and thereafter when the roof is built-up becomes a permanent part of the roof. However, when the size of the roof-top equipment is unknown at the time of roof construction, problems still exist when use is made of such roof curbs. For example, if the required roof-top unit is larger than initially expected, the curb platform either has to be cut bigger or the platform and/or curb itself torn out completely, thereby penetrating the integrity of the roof. If the unit is smaller than originally anticipated, the curb platform must be modified by "jury rigging" at the site at relatively large cost--usually by unskilled workers, subsequently resulting in leakage problems. A similar situation results when, for example, one tenant in a shopping mall moves and a later tenant having a greater heat load requires a larger roof-top air conditioning unit, the prior art curb platform had to be cut or the platform and/or curb replaced thereby compromising the integrity of the roof, resulting in eventual leakage problems. If the later tenant requires a smaller unit, the curb platform must be modified, ensuring eventual leakage problems. Moreover problems are encountered with the prior art curbs since they lack water run-off provisions because the curbs had to have substantially flat platforms for directly carrying the roof-top equipment. Furthermore, the prior art constructions are such that the curb platform greatly sags when carrying the load of the roof-top unit and this is aggravated further when additional loads such as snow accumulation occur. The inherent lack of rigidity of the structure effects a rapid deterioration of integrity of the unit further resulting in leakage problems.